.bg {
		background:#000;
		width: 100%;
		height: 100%;
		left:0;
		top:0;/*FF IE7*/
		filter:alpha(opacity=30);/*IE*/
		opacity:0.3;/*FF*/
		z-index:1;
		position:fixed!important;/*FF IE7*/
		position:absolute;/*IE6*/
		_top:    expression(eval(document.compatMode &&
		            document.compatMode=='CSS1Compat') ?
		            documentElement.scrollTop + (document.documentElement.clientHeight-this.offsetHeight)/2 :/*IE6*/
		            document.body.scrollTop + (document.body.clientHeight - this.clientHeight)/2);/*IE5 IE5.5*/

}
